Altitude acclimation is just as important as getting into physical condition. And the conditioning will NOT help you acclimate!
If you can get to a summit a few days before, that will help. But the best way to acclimate is to spend two nights at 8-10,000 ft elevation before you start your hike. Whitney Portal is 8,000, and Horseshoe Meadows is 10,000.
Horseshoe meadows has walk-in camp sites that always seem to be available.